GPS and geofence time clocks for cleaning, security and construction crews

When your people work at customers' addresses, not in your building, a wall-mounted time clock is no use. Paper sheets and text messages fill the gap, badly. A GPS time clock with a geofence lets each worker clock in on their own phone and records where they were when they did. This guide explains how it works, how to set it up for cleaning, security and construction crews, what GPS can and cannot prove, and how to introduce it without losing your team's trust.

How a geofenced time clock works

1. Each job site, customer or post has an address and a geofence: a circle of a set radius around a point, for example 150 meters around the building's entrance.
2. The worker opens the app and taps clock in. The phone reports its position and an accuracy estimate.
3. The system records the time from its own clock, the position, the accuracy and the distance from the site.
4. If the position is inside the circle, the clock in is verified. If not, it is still recorded, but flagged as an exception for a supervisor to review.
5. The same happens at clock out. The hours between become the timesheet.

The distance is a straight-line calculation between two coordinates. You can test it with the free geofence distance checker, including with your phone's own location.

Setting the radius

Too small and honest workers get flagged every day; too large and the fence proves little. Start from the site:

Site	Starting radius	Why
House or small office	100 to 150 m	Covers parking on the street and indoor GPS drift.
Apartment block or office tower	150 to 250 m	Tall buildings reflect signals; indoor readings drift more.
Retail unit in a mall	200 to 300 m	Large roofs and car parks.
Construction site, campus, warehouse yard	The site's size plus 100 m	Workers clock in at different gates.

Put the center where workers actually arrive, such as the main gate or entrance, not the middle of the lot. Review exceptions after two weeks and adjust sites that flag honest clock ins.

What GPS can and cannot prove

It can show

• The phone was near the site when the worker clocked in and out.
• The pattern over time: a worker who is always 2 km away at clock in is a conversation to have.
• The time, from the server, not the phone's clock, which can be changed.

It cannot show

• That the worker stayed between clock in and clock out, unless you track location all day, which most teams should not.
• That the person holding the phone is the worker. Each worker should have their own login; never share accounts.
• An exact position indoors. Phones often report positions 30 to 100 meters off inside buildings, and say so in their accuracy estimate. Treat a reading just outside the fence with poor accuracy as uncertain, not as a violation.

Combine GPS with things that show the work: a checklist ticked during the shift, a note or report, and a customer or site contact's signature.

By industry

Cleaning

Crews move between several addresses a day, often with short visits. Use a geofence per address, a cleaning checklist per job type, and a customer sign-off at the end. Recurring jobs should repeat on their own so the schedule is always ready. Watch the time between jobs: in many cases drive time between customers during the day counts as hours worked.

Security

Officers work long shifts at one site. The clock in proves the post was covered from the start; a missing clock in a few minutes after the shift start should alert a supervisor while there is still time to send cover. Post orders become a checklist, and the shift report goes to the client. Long shifts and double shifts push officers into overtime quickly, so show weekly hours while scheduling.

Construction

Sites are large and change shape. Use a generous radius, centered on the main gate. Clock in by site puts labor cost on the right job. A daily log at the end of each shift records who was there, what was done and any delays. Crew members often work at different rates in the same week, so overtime needs the weighted regular rate; the overtime and blended rate calculator shows how.

Privacy and trust

The fastest way to fail is to surprise your team. Before you start:

• Say exactly what is recorded. Position at clock in and clock out only, not all day, not off the clock.
• Put it in writing. A short policy that says what is collected, why, who sees it and how long it is kept. Some states have specific notice or consent rules for location tracking of employees; check yours.
• Use it fairly. An exception is a question, not an accusation. Resolve it with a reason code and move on.
• Show the benefit. Verified hours end disputes about pay. Workers who are paid for every minute they worked tend to like the system.
• Plan for no phone. Have a process for a dead battery or a worker without a smartphone: the supervisor enters the time with a reason.

Rolling it out

1. Load sites with addresses and set a radius for each.
2. Run one crew for two weeks. Review every exception and adjust radii.
3. Train the rest in person: add the app to the home screen, clock in, checklist, clock out.
4. Review exceptions daily for the first month, then weekly.
5. Pay from the verified, approved timesheets, and invoice from the same hours.

For timesheets the customer signs, read Moving from paper timesheets to signed digital timesheets.